1// Copyright (c) 2012 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include "ipc/ipc_channel.h" 6 7#include <limits> 8 9#include "base/atomic_sequence_num.h" 10#include "base/rand_util.h" 11#include "base/strings/stringprintf.h" 12 13#if !defined(OS_NACL) 14namespace { 15 16// Global atomic used to guarantee channel IDs are unique. 17base::StaticAtomicSequenceNumber g_last_id; 18 19} // namespace 20#endif 21 22namespace IPC { 23 24// static 25std::string Channel::GenerateUniqueRandomChannelID() { 26 // Note: the string must start with the current process id, this is how 27 // some child processes determine the pid of the parent. 28 // 29 // This is composed of a unique incremental identifier, the process ID of 30 // the creator, an identifier for the child instance, and a strong random 31 // component. The strong random component prevents other processes from 32 // hijacking or squatting on predictable channel names. 33 34 int process_id = base::GetCurrentProcId(); 35 return base::StringPrintf("%d.%u.%d", 36 process_id, 37 g_last_id.GetNext(), 38 base::RandInt(0, std::numeric_limits<int32>::max())); 39} 40 41} // namespace IPC 42 43